The present invention relates to a head-mounted display device whereby an image display section can be worn on the head of an observer.
A head-mounted display device enables various information to be displayed in a simple manner, by means of a small, lightweight display device worn on the head of an observer.
Conventionally, the display device and a device for generating drive signals for the display device are combined directly. Furthermore, the display device and an optical system, which changes the light path in order to direct display light emitted from the display device towards the observer""s eye, are also combined directly. In other words, the display device, optical system and drive signal generating device are located in a concentrated fashion in front of the observer""s eye. For this reason, there have been problems in that the weight of the device has an unbalancing effect on the observer, thereby reducing the wearing comfort.
Consequently, it has been thought that the weight balance of the device can be improved by coupling the display device and optical system directly and positioning the driving circuit beside the side of the observer""s head. However, if the display device and optical system are coupled together directly in front of the observer""s eyes, then a problem arises in that the observer""s field of vision is restricted by the display device.
It is an object of the present invention to provide a head-mounted display device which is capable of resolving the foregoing problems.
The present invention is a head-mounted display device, wherein a display device for emitting image display light, an optical system for changing the light path of the display light in order to direct the light towards the eye of an observer, and a drive signal generating device for the display device, are worn on the head of the observer, characterized in that the display device is located in such a manner that the display light is emitted in a forward direction from a position separated radially from the visual axis of the observer when looking straight ahead; the optical system is located in front of the display device with an interval; and the drive signal generating device is located in a position that is separated radially from the visual axis and separated with an interval from the display device and optical system.
According to the constitution of the present invention, the image display light emitted from the display device travels in a forward direction from a position separated radially from the visual axis of the observer when looking straight ahead, whereupon the light path of the display light is changed by the optical system and directed towards the eye of the observer. Thereby, an image is seen by the observer.
Since the display device, optical system and drive signal generating device are mutually separated by intervals, it is possible to prevent the weight of the device from having an unbalancing action on the observer. Moreover, since the display device and drive signal generating device are located in positions separated radially from the visual axis of the observer looking straight ahead, it is possible to prevent restriction of the observer""s field of vision.
In cases where a circuit is required for driving the display device in accordance with signals transmitted from the drive signal generating device, this drive circuit can be integrated with the display device, or it can be integrated with the drive signal generating device, or it can be formed separately from both of these elements. In cases where a liquid crystal display panel with a back light is used for the display device, for example, then the driving circuit can be a driver for driving the liquid crystal display element.
If a circuit is required for lighting the light source for the image display light emitted from the display device in accordance with signals transmitted from the drive signal generating device, then this lighting circuit can be integrated with the display device, or it can be integrated with the drive signal generating device, or it can be formed separately from both of these elements. If a liquid crystal display panel with back light is used as the display device, for example, then the lighting circuit is a back light lighting circuit.
Desirably, the display device is located directly below the visual axis.
Thereby, it is possible to position the display device as closely as possible to the face of the observer, directly below the observer""s eye. Consequently, it is possible almost completely to prevent any restriction of the observer""s field of vision due to the display device.
Desirably, the optical system is coupled to the display device by means of a coupling member, in such a manner that the light path of the display light is changed directly below the visual axis. Thereby, any restriction of the observer""s field of vision due to the optical system and coupling member can be reduced.
Desirably, the drive signal generating device is located behind the display device with an interval, beside the side of the head of the observer.
Thereby, the field of vision of the observer is not restricted by the drive signal generating device. Moreover, when the display device and optical system are positioned directly below the observer""s visual axis, then it is possible to prevent more reliably any unbalancing effect on the observer due to the weight of the device of the present invention.
Desirably, the display light is directed towards one eye of the observer; a housing for covering the drive signal generating device is coupled to the holding member beside the side of the head of the observer; the optical system is connected to the display device in such a manner that it is located in a position separated radially from the visual axis; and the display device is movably in a spherical plane relative to the housing covering the drive signal generating device, in front of the face of the observer. According to this constitution, it is possible to move the display device along a spherical plane with respect to the drive signal generating device, in front of the observer""s face. By means of this movement, the display device and optical system can be rotated about axes running in the vertical direction and lateral direction of the observer""s head, at the least. Thereby, it is possible to adjust the direction of travel of the image display light whose light path is changed by the optical system. Consequently, an image can be formed in a position suitable for viewing by any observer, even if there is wide variation between the shapes of different observers"" heads. Moreover, since the display device can be moved in front of the observer""s face, fine adjustment of the image position can be carried out readily.
Desirably, the housing covering the drive signal generating device is coupled movably in a spherical plane to the holding member, beside the side of the head of the observer. Thereby, the drive signal generating device can be moved in spherical plane with respect to the holding member, beside the side of the observer""s head, and moreover, the display device can be moved in a spherical plane with respect to the drive signal generating device, in front of the observer""s face. Consequently, fine adjustment of the image position can be carried out swiftly.
Desirably, the holding member comprises left and right side head pads which press against the left and right sides of the head of the observer in the regions surrounding the ears, and left and right holders for holding the pads, openings being formed in the center of the pads and the center of the holders, in such a manner that the ears of the observer is exposed.
Since the movement of the holding member with respect to the head is restricted by means of the holding member pressing against the head via the left and right side head pads, it is possible to prevent occurrence of shaking in the display device or optical system, thereby preventing degradation of viewing characteristics. Since the left and right side head pads press against the regions of the head surrounding the ears, the position restricting the movement of the holding member with respect to the head covers a broader range than cases where the aforementioned pads press against the ears. Consequently, movement of the holding member with respect to the head can be restricted more securely. Since an opening is formed in the center of each pad and the center of each holder, thereby exposing the observer""s ears, the observer""s hearing is not restricted.
Desirably, the pads and the holders have a continuous ring shape. Thereby, it is possible to restrict movement of the holding member with respect to the head, more securely.
Desirably, the pressing force exerted via the pads on the left and right sides of the head in the regions surrounding the ears is greater in front of the ears than behind the ears.
When the display device is located in front of the position at which the display unit and holding member are coupled together, and the optical system is positioned in front of the display device, then any shaking of the image can be restricted more reliably by making the pressure exerted via each pad greater in front of the ears than behind the ears.
Desirably, the holding member comprises a coupling section for coupling the left and right holders; the holders are each coupled to the coupling section, swingably about an axis in the vertical direction; and pressing sections for pressing against the holders via elastic members are provided on the coupling section, in such a manner that an elastic force is imparted causing the front side of each holder to swing towards the side of the head of the observer.
Thereby, the pressure exerted via each pad can be made greater in front of the ears than behind the ears, by the action of elastic force. Furthermore, by means of a swinging movement of the holders, each pad can be made to follow the shape of the observer""s head. Therefore, shaking of the image can be restricted reliably, even if there are individual differences in head shape.
Desirably, there is provided means for imparting an elastic force which narrows the interval between the left and right holders behind the ears of the observer. Thereby, the pads can be prevented from moving away from the head in the region behind the ears, even if the pressure exerted via the pads is greater in front of the ears than behind the ears. Consequently, shaking of the image can be restricted more reliably.
Desirably, left and right upper head pads pressed against the left and right upper portions of the head of the observer are coupled to the coupling section. Thereby, movement of the holding member with respect to the head can be restricted more reliably.
According to the present invention, it is possible to provide a head-mounted display device wherein any restriction of the observer""s field of vision is prevented and wearing comfort is improved, thereby reducing visual fatigue in the observer and fatigue due to the weight of the device. Moreover, it is possible to provide a head-mounted display device which ensures a sufficient field of view, reduces the burden on the observer, and enables fine adjustment of the position where display images are formed to be carried out readily and swiftly. Moreover, shaking of images can be restricted, thereby improving viewing characteristics, without restricting the observer""s hearing.